Positron Emission Tomography (PET) using (18F)-2-deoxyglucose (FDG) allows us to obtain anatomical data (e.g., axial transverse or coronal images of the brain) as well as dynamic functional data (such as regional cerebral glucose consumption rate, and measurement of storage, degradation and turnover of tagged metabolites). Besides FDG, other radiopharmaceuticals (e.g., those tagged with 15-0,11C, 13N) can be used with PET to study the BBB, oxygen metabolism, protein syntnesis, and neuroreceptors. The unique property of PET is that it provides physiologic and pathophysiologic information not available with any other imaging procedure. Since June, 1982 we have been using a high-resolution, high-sensitivity scanner built in our Section, the Neuro-PET. The performance of this scanner has exceeded all our expectations. This device has made possible new applications of the PET technique.